1. Field of the Invention
The present invention concerns a resin composition which contains polyphenylene ether and a polyester and characterized by excellent mechanical properties and oil resistance.
2. Brief Description of the Prior Art
Although polyphenylene ether exhibits various excellent properties (e.g., high heat resistance as well as excellent strength, electrical properties, and dimensional precision), said resin is easily degraded by aromatic hydrocarbons (e.g., benzene, etc.) or halogenated hydrocarbons (e.g., Triclene, etc.). Since the molding efficiency is inferior, furthermore, said resin is seldom used as a single molded product.
To improve the molding efficiency of polyphenylene ether, attempts have been made to mix in a polystyrene resin. If this method is implemented, the molding efficiency is improved, but since the polystyrene resin is also degraded by aromatic hydrocarbons (e.g., benzene, etc.) or halogenated hydrocarbons (e.g., Triclene, etc.), it is impossible to improve the solvent resistance by adding said polystyrene resin.
Attempts have also been made to add a thermoplastic polyester resin to simultaneously improve the molding efficiency and solvent resistance (see Japanese Kokai Patent No. Sho 59[1984]-159847). Since the miscibility between the polyphenylene ether and thermoplastic polyester is inferior, however, the mechanical strength of a molded product derived from the resulting mixture is inevitably inferior.
If a compound which contains at least one group selected from among carboxyl groups, acid anhydride groups, acid amide groups, imide groups, carboxylic acid ester groups, epoxy groups, amino groups, and a hydroxyl group is added to a polyphenylene ether-polyester mixture as a third component, a resin composition which yields a molded product characterized by excellent bending elasticity, heat resistance, molding efficiency, and water resistance is allegedly obtained (see Japanese Kokoku Patent No. Sho 63[1988]-350).
It has also been proposed that a resin composition which yields a molded product characterized by excellent physical appearance, impact resistance, molding efficiency, dimensional precision, and chemical resistance can be obtained by adding a bifunctional epoxy compound (see Japanese Kokoku Patent No. Sho 63[1988]-39958).
Attempts have also been made to enhance the dispersibility between the polyphenylene ether and polyester by adding a polymer which has been obtained by reacting an epoxy group-containing polyphenylene ether with a polyester (see Japanese Kokoku Patent No. Sho 63[1988]-125569).